Portable memory devices sometimes store “preview content.” Preview content can be a full or partial version of content, such as a song or video, but access to the preview content expires according to an access rule (e.g., after three plays, after one week, after three plays in one week, etc.). The preview content can entice a user to purchase the content in a fuller-access, non-preview form (e.g., a song with unlimited plays), and the user can be provided with a mechanism for making such a purchase, typically after the last time the preview content can be accessed. When access to the preview content expires, the preview content can no longer be accessed by anyone. While this mechanism prevents the user from continuing to access the preview content in violation of the access rules, it also prevents a second user who subsequently obtains the portable memory device from accessing the preview content (e.g., when the original user lends, sells, or otherwise provides the portable memory device to the second user). Accordingly, the second user is not exposed to the preview content, thereby eliminating an opportunity to entice the second user to purchase the content.